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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
351

Antioxidant And Cytotoxic Properties Of Salvia Absconditiflora And Effects On Cyp1a1, Cyp1b1 Gene Expressions In Breast Cancer Cell Lines

Yilmaz, Selis 01 January 2013 (has links) (PDF)
Salvia genus is a widely cultivated genus and used in medicine for various purposes as having antimicrobial, antioxidant, anticarcinogen and anti-inflammatory features. In this study the aim was to investigate phenolic composition of Salvia absconditiflora and understand the possible effects of those constituents in cancer related drug metabolizing enzymes. Salvia absconditiflora showed 80,43 % Radical Scavenging Activity against DPPH radical. Total flavonoid content was found as one third of total phenolic content. Presence of important phenolic acids and flavonoids such as caffeic acid, luteolin, coumaric acid are validated with LC-MS/MS analysis. Cytotoxicity of Salvia absconditiflora treatment on MCF-7 and MDA-MB-231 breast cancer cell lines were investigated through XTT and TBE assays both dose and time dependent manner. Cell proliferation was inhibited 50 % by different IC50 values calculated in different assays and different time intervals. This suggests that two breast cancer cell lines response in a different way to cytotoxic treatments. Cancer related drug metabolizing enzyme gene modulations were investigated with qRT-PCR. CYP1A1 and CYP1B1 were upregulated in MCF-7 but down-regulated in MDA-MB-231 cells in response to Salvia absconditiflora treatment.
352

Antioxidant And Cytotoxic Properties Of Salvia Absconditiflora And Effects On Cyp1a1, Cyp1b1 Gene Expressions In Breast Cancer Cell Lines

Yilmaz, Selis 01 January 2013 (has links) (PDF)
Salvia genus is a widely cultivated genus and used in medicine for various purposes as having antimicrobial, antioxidant, anticarcinogen and anti-inflammatory features. In this study the aim was to investigate phenolic composition of Salvia absconditiflora and understand the possible effects of those constituents in cancer related drug metabolizing enzymes. Salvia absconditiflora showed 80,43 % Radical Scavenging Activity against DPPH radical. Total flavonoid content was found as one third of total phenolic content. Presence of important phenolic acids and flavonoids such as caffeic acid, luteolin, coumaric acid are validated with LC-MS/MS analysis. Cytotoxicity of Salvia absconditiflora treatment on MCF-7 and MDA-MB-231 breast cancer cell lines were investigated through XTT and TBE assays both dose and time dependent manner. Cell proliferation was inhibited 50 % by different IC50 values calculated in different assays and different time intervals. This suggests that two breast cancer cell lines response in a different way to cytotoxic treatments. Cancer related drug metabolizing enzyme gene modulations were investigated with qRT-PCR. CYP1A1 and CYP1B1 were up-regulated in MCF-7 but down-regulated in MDA-MB-231 cells in response to Salvia absconditiflora treatment.
353

Cell Targeted Ribosome Inactivating Proteins Derived from Protein Combinatorial Libraries

Perampalam, Subodini 01 August 2008 (has links)
Combinatorial protein libraries based on a protein template offer a vast potential for deriving protein variants harboring new receptor specificity while retaining other tem-plate functions to serve as library search-engines, cell-routing sequences and therapeutic domains. This concept was tested with the design and synthesis of protein libraries where short random peptide motifs were embedded directly within the catalytic A subunit of the bacterial ribosome-inactivating protein (RIP) known as Shiga-like toxin 1 (SLT-1). More precisely, a seven amino acid peptide epitope (PDTRPAP) was inserted between residues 245-246 of its A subunit (SLT-1APDTRPAP) and shown to preserve catalytic function while exposing the epitope. SLT-1 A chain libraries harboring tripep-tide and heptapeptide random elements were subsequently constructed, screened and shown to express more than 90% of expected cytotoxic A chain variants. Finally, more than 9,000 purified SLT-1 A chain variants were screened using their ribosome-inactivating function in a cell-based assay to identify mutants that are able to kill human melanoma 518-A2 cells. This search led to the striking discovery of a single chain RIP that displays selectivity for a panel of human melanoma cell lines as well as minimal immunogenicity when injected repeatedly into mice. This directed evolution of a RIP template provides a broad platform for identifying cell type specific cytotoxic agents.
354

Investigating the Relationship Between Structure, Ice Recrystallization Inhibition Activity and Cryopreservation Ability of Various Galactopyranose Derivatives

Tokarew, Jacqueline 31 May 2011 (has links)
The goal of our research is to generate cryopreservation agents derived from antifreeze glycoproteins. One postulated mechanism of cell cryo-injury is ice recrystallization. It is known that simple saccharides and cryopreservation agents (DMSO) display ice recrystallization inhibition (IRI). This study assessed the cytotoxicity and cryopreservation ability of these sugars in relation to their IRI. It was determined that compounds with greater IRI have increased cytotoxicity yet confer cryoprotection. To further investigate how structure is affecting IRI activity, several galactopyranoside derivatives were synthesized. A series of deoxy and α-Callyl- deoxy galactopyranoses were prepared. Testing determined that removal of any hydroxyl group removes IRI. 3-deoxy-β-thiophenyl galactose was also synthesized and had surprisingly better IRI than β-thiophenylgalactose. Also, 6-azido galactose had similar IRI to 6-deoxy galactose. Lastly, a series of β- thioalkylgalactosides was synthesized and testing gave contradicting results which suggest that predicting IRI based on hydrophilicity is more complicated than initially hypothesized.
355

Disease mechanisms in the C3H/HeJ Mouse Model of Alopecia

Barekatain, Armin 05 1900 (has links)
Alopecia areata (AA) is a chronic inflammatory disease of hair follicles manifesting as patchy areas of hair loss on the scalp and body. Development of AA is associated with pen- and intra-follicular inflammation of anagen stage hair follicles, primarily by CD4+ and CD8+ cells. We hypothesized that if cell-mediated cytotoxicy against hair follicles is to be a component of the hair loss disease mechanism, increased expression of genes and products typical of cytotoxic cells, as well as increased apoptosis activity within affected hair follicles, would be expected to occur in the lesional skin compared to the normal skin. Furthermore, we studied gene expression levels of multiple cytokines and characteristic chemokines, using the C3FI/HeJ mouse model of AA. mRNA expression levels of granzyme A, granzyme B, perform Fas, Fas ligand, TNF-cL, TNF-aRl and R2, TRAIL, TRAILR, TRAMP, Thi-, Th2-, and Th17-associated cytokines, as well as multiple chemokines were compared between the skin, draining lymph nodes, thymus and spleens of normal and AA-affected mice using quantitative reverse transcriptase PCR. FasL, granzyme A, granzyme B, pro- and anti-inflammatory cytokines were all highly up-regulated in the skin of AA-affected mice. Immunohistochemical studies of the skin revealed that, although greater numbers of granzyme B and FasL expressing cells were present in AA affected skin, the cells were morphologically diffusely distributed and not exclusively located within the focal pen- and intrafollicular infiltrate. The majority of these cells were further characterized as mast cells, which were also found in substantially greater numbers in the skin of mice with AA compared to their normal haired controls. Almost no perform expressing cells were identified in AA affected mouse skin and TUNEL staining suggested relatively limited apoptosis activity in hair follicle keratinocytes. In conclusion, while granzymes and FasL may play important roles in disease development, the profiles and patterns of expression are not consistent with direct cell-mediated cytotoxic action against the follicular epithelium in chronic mouse AA. Potentially, hair growth inhibiting cytokines may play a more dominant role in AA development than previously thought. Furthermore, mast cells, with their increased presence around hair follicles in the AA affected mouse skin and their ability to express granzyme B and FasL, are suggested as potential key players in the pathogenesis of AA.
356

Development of Organ-Specific Progenitor Cell Cultures as Efficacy Test Platforms for Electron-Spun Fibre Meshes in Regenerative Medicine Applications

Rajendran, Vijayalakshmi January 2011 (has links)
The nervous and cardiovascular system plays the most complex and vital role in all organisms. Any damage or injury to these essential organs in our body results in long term irreversible impairment or death. The main goal of the regenerative medicine is to repair or recreate tissues using stem cells to restore the vital function of the targeted organ. Along with organ specific stem/progenitor cells, non-toxic, biodegradable synthetic polymers are also needed for an effective reparative therapy. The effect of PCL materials and surface modified (PEDOT coated) PCL materials of different topology with neural progenitor cells as test platforms are evaluated for cytotoxicity and neuron differentiation. The stem cells from heart are isolated and characterized as cardiac stem cells by Fluorescence activated cell sorting through specific antigen expression. The cardiac stem cells are used to establish effective proliferation and differentiation system. Hence, developing cardiac and neural progenitor cell cultures as an efficacy test platforms for biomaterials of different diameter and orientation benefits respective tissue engineering with proper restoration of function. Further, the nerve and cardiac tissue rejuvenation would serve as a regenerative therapy for numerous neurodegenerative disorders and cardiovascular disorders like myocardial infarction respectively.
357

A Study of the Process and Causes of Abeta(25-35) Amyloid Formation

Ridinger, Katherine V. 2009 December 1900 (has links)
Amyloid fibrils results from a type of ordered polypeptide aggregation that is associated with ailments such as Alzheimer's disease (AD). Annually, millions of people in the United States alone develop and die from AD. Therefore, it is necessary to understand not only the process of amyloid formation, but also the causes of this specific type of aggregation. This study used ABeta(25-35) since it is a fragment of the Alzheimer?s peptide that behaves like the full length peptide found in patients with AD. To study the process of amyloid formation, several methods were used so that a more complete picture of the stepped aggregation process could be realized. Several oligomeric species were detected and described many of which could not have been observed without using the complete battery of methods utilized here. The oligomeric species detected included a novel 'rolled sheet' that appeared to be the immediate precursor of amyloid fibrils, and two supermolecular species that appear after amyloid fibrils were formed. In determining the causes of amyloid formation, two significant discoveries were made. First, by partial sequence randomization, truncation, and Ala scanning mutagenesis, the critical amyloidogenic region of ABeta(25-35) was found to be residues 30-35. This critical core region is important because it is thought to be the region that initiates amyloid formation, therefore knowing the residues involved in the region is a useful tool for developing methods of fibril formation prevention. Second, by inserting all naturally occurring amino acids into position 34 of ABeta(25-35), three distinct classes of variants were observed and the effect of several physiochemical properties on amyloidosis were examined. Hydrophobicity, solubility, and ?-strand propensity were found to affect aggregation to the greatest extent. Also within these two studies, our results suggest that early oligomers are the cytotoxic species as opposed to amyloid fibrils or other larger macromolecular assemblies.
358

Hplc-dad Isolation Of Antioxidant Compounds In Aesculus Hippocastanum Bark Extracts And Cytotoxic Effects On Hl-60 Cells

Ozdogan, Nizamettin 01 September 2007 (has links) (PDF)
This study was designed to investigate the cytotoxic and antioxidative properties of Aesculus hippocastanum L. (A. hippocastanum) bark extracts. Dried and powdered barks were extracted in ethanol, methanol, water and ethylacetate at a ratio of 1:6 (w/v). Antioxidative capacity of each extract (ethanol, methanol, water and ethylacetate) were determined by their ability to scavenge 1, 1 -diphenyl-2-picryl-hydrazyl radical (DPPH). Effective concentration (EC50) values were calculated as 0.010 mg/mL 0.011 mg/mL, 0.009 and 0.019 mg/mL, respectively for ethanol, methanol, ethylacetate and aqueous extracts. The highest DPPH radical scavenging activity was demonstrated by ethyl acetate among the four bark extracts of A. hippocastanum. Nevertheless, methanol extract was preferred for the separation, identification and further quantification of its phenolic compounds using HPLC method. Analytical and semi&ndash / preparative HPLC methods were applied to qualify and quantify the isolates. Human Myeloid Leukemia (HL - 60) cell line was used as a model system for the proliferation studies. HL - 60 cells were cultured in the presence of various concentrations (0 to 100 &micro / g/mL) of methanol bark extract and, also, with the various concentrations of standard esculetin. HL-60 cell viability was examined by tryphan blue and the metabolism of tetrazolium salt XTT (2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino) -carbonyl]-2H-tetrazolium hydroxide). XTT effective dose (ED50) values for the proliferation studies of methanol extract and standard esculetin were calculated as 56.18 &micro / g/mL and 21.23 &micro / g/mL, respectively. These results suggested that A. hippocastanum methanol bark extract and esculetin could be considered as a potent antioxidant and cytotoxic agent.
359

Comparative Effects Of Emodin On Biological Activities Of Mcf-7 And Mda-231 Cell Lines

Sakalli, Elif 01 December 2010 (has links) (PDF)
Emodin (1,3,8-trihydroxy-6-methylanthraquinone) is a phytoestrogenic component of Rheum plant extracts which has been used for medical treatment since ancient times. It has been shown to have anti-inflammatory and anti-cancer effects. In our research, we aimed to study the biological effects of emodin on MCF-7 and MDA-231 cell lines. Cytotoxicity assays showed that emodin treatment for 48hours caused a concentration dependent decrease in viable cell numbers of both cell lines. As determined by cell counting with tryphan blue, IC50 values were 8.40 and 12.17 &micro / g/ml for MCF-7 and MDA-231 cells, respectively. Apoptotic effects of emodin was investigated by measuring the changes in apoptotic and antiapoptotic gene expressions by qRT-PCR. In MCF-7 cells, Bax expression increased with increasing emodin concentrations, while Bcl-2 expression was downregulated. Bax/Bcl-2 ratio was calculated as 9.2 fold at 10&micro / g emodin/ml treatment for 48 hours, indicating stimulation of apoptosis. However, Bax/Bcl-2 ratio was found 1.6 fold for MDA-231 cells. These results were in accordance with the results obtained from microarray analysis of related gene expressions. MCF-7 cells were more apoptotic in comparison to MDA-231 cells. DNA fragmentation was observed in MCF-7 cells by TUNEL method. GST enzyme activity that was measured using CDNB as substrate, was increased 100% with respect to control up to 5&micro / g emodin/ml treatment of MCF-7 cells for 48 hours. However, effect of emodin on GST activity in MDA-231 cells was found insignificant. According to microarray analysis results, emodin affected the gene expressions of GST isozymes in MCF-7 cells much more than in MDA-231 cells.
360

Lipid peroxide and transition metals are required for the toxicity of oxidized low density lipoprotein to cultured endothelial cells

Kuzuya, Fumio, Asai, Kanichi, Hayashi, Toshio, Funaki, Chiaki, Naito, Michitaka, Kuzuya, Masafumi 02 1900 (has links)
名古屋大学博士学位論文 学位の種類 : 博士(医学)(課程) 学位授与年月日:平成3年3月8日 葛谷雅文氏の博士論文として提出された

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